Cyclopenta[I] phenanthrene-metal complex catalyst systems

ABSTRACT

In a process for preparing polymers based on monomers having a C═C double bond by homopolymerization or copolymerization of these monomers in the presence of a catalyst system comprising a metallocene complex A) and a compound B) capable of forming metallocenium ions and, if desired, an organometallic compound of main group I, II or III of the Periodic Table of the Elements C), the metallocene complex A) used is a compound of the formula (I)                    
     where the substituents and indices have the following meanings: 
     R 1  to R 11  are hydrogen, C 1 -C 10 -alkyl, 5- to 7-membered cycloalkyl which may in turn bear C 1 -C 6 -alkyl groups as substituents, C 6 -C 15 -aryl or arylalkyl, where two adjacent radicals R 1  to R 8  may together form a cyclic group having from 4 to 15 carbon atoms, or Si(R 12 ) 3 , 
     where R 12  is C 1 -C 10 -alkyl, C 6 -C 15 -aryl or C 3 -C 10 -cycloalkyl, 
     M is a metal of transition groups III to VI of the Periodic Table of the Elements or a metal of the lanthanide series, 
     X are identical or different and are hydrogen, halogen, C 1 -C 10 -alkyl, C 6 -C 15 -aryl, C 1 -C 10 -alkoxy or C 6 -C 15 -aryloxy and 
     n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1.

BACKGROUND AND BRIEF SUMMARY OF THE INVENTION

The present invention relates to a process for preparing polymers basedon monomers having a C═C double bond by homopolymerization orcopolymerization of these monomers in the presence of a catalyst systemcomprising a metallocene complex A) and a compound B) capable of formingmetallocenium ions and, if desired, an organometallic compound of maingroup I, II or III of the Periodic Table of the Elements C), catalystsystems which are suitable for polymerizing monomers having a C═C doublebond and comprise as active constituents

A) a metallocene complex of the formula (I)

where the substituents and indices have the following meanings:

R¹ to R¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals R¹ to R⁸ may together form acyclic group having from 4 to 15 carbon atoms, or Si(R¹²)₃,

where R¹² is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

M is a metal of transition groups III to VI of the 40 Periodic Table ofthe Elements or a metal of the lanthanide series,

X are identical or different and are hydrogen, halogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, C₁-C₁₀-alkoxy or C₆-C₁₅-aryloxy

and

n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1,

B) a compound capable of forming metallocenium ions and, if desired, C)an organometallic compound of main group I, II or III of the PeriodicTable of the Elements, metallocene complexes of the formula (I)

where the substituents and indices have the following meanings:

R¹ to R¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals R¹ to R⁸ may together form acyclic group having from 4 to 15 carbon atoms, or Si(R¹²)₃,

where R¹² is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

M is a metal of transition groups III to VI of the Periodic Table of theElements or a metal of the lanthanide series,

X are identical or different and are hydrogen, halogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, C₁-C₁₀-alkoxy or C₆-C₁₅-aryloxy

and

n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1.

The present invention further relates to polymers which are based onmonomers having a C═C double bond and are obtainable byhomopolymerization or copolymerization of these monomers in the presenceof a catalyst system comprising a metallocene complex A) and a compoundB) capable of forming metallocenium ions and, if desired, anorganometallic compound of main group I, II or III of the Periodic Tableof the Elements C), and also fibers, films and moldings comprising thesepolymers and the use of metallocene complexes (I) as components incatalyst systems or as catalysts.

Syndiotactic polymers of styrene are known. Owing to their propertyprofile, eg. high hardness, high stiffness, dimensional stability andlow dielectric constants, they can be used, for example, as electricalor mechanical components.

DETAILED DESCRIPTION OF THE INVENTION

It is an object of the present invention to find novel catalyst systemswhich can be used at relatively high polymerization temperatures,preferably above 60° C., have a high polymerization activity and give apolymer having a high proportion, preferably above 80% (determined byextraction of the crude polymer with n-butanone) of syndiotacticstructural units and a high molecular weight M_(w).

We have found that this object is achieved by a process for preparingpolymers based on monomers having a C═C double bond byhomopolymerization or copolymerization of these monomers in the presenceof a catalyst system comprising a metallocene complex A) and a compoundB) capable of forming metallocenium ions and, if desired, anorganometallic compound of main group I, II or III of the Periodic Tableof the Elements C), wherein the metallocene complex A) used is acompound of the formula (I)

where the substituents and indices have the following meanings:

R¹ to R¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals R¹ to R⁸ may together form acyclic group having from 4 to 15 carbon atoms, or Si(R¹²)₃,

where R¹² is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

M is a metal of transition groups III to VI of the Periodic Table of theElements or a metal of the lanthanide series

X are identical or different and are hydrogen, halogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, C₁-C₁₀-alkoxy or C₆-C₁₅-aryloxy

and

n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1,

by catalyst systems which are suitable for polymerizing monomers havinga C═C double bond and comprise as active constituents

A) a metallocene complex of the formula (I)

B) a compound capable of forming metallocenium ions and, if desired,

C) an organometallic compound of main group I, II or III of the PeriodicTable of the Elements, by metallocene complexes of the formula (I)

where the substituents and indices have the following meanings:

R¹ to R¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals R¹ to R⁸ may together form acyclic group having from 4 to 15 carbon atoms, or Si(R²)₃,

where R¹² is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

M is a metal of transition groups III to VI of the Periodic Table of theElements or a metal of the lanthanide series,

X are identical or different and are hydrogen, halogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, C₁-C₁₀-alkoxy or C₆-C₁₅-aryloxy

and

n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1,

by polymers which are based on monomers having a C═C double bond and areobtainable by homopolymerization or copolymerization of these monomersin the presence of a catalyst system comprising a metallocene complexA), a compound B) capable of forming metallocenium ions and, if desired,an organometallic compound of main group I, II or III of the PeriodicTable of the Elements C), wherein the metallocene complex A) used is acompound of the formula (I)

where the substituents and indices have the following meanings:

R¹ to R¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals R¹ to R⁸ may together form acyclic group having from 4 to 15 carbon atoms, or Si(R¹²)₃,

where R¹² is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

M is a metal of transition groups III to VI of the Periodic Table of theElements or a metal of the lanthanide series,

X are identical or different and are hydrogen, halogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, C₁-C₁₀-alkoxy or C₆-C₁₅-aryloxy

and

n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1,

by fibers, films and moldings comprising the polymers of the presentinvention and also by the use of the metallocene complexes (I) of thepresent invention as components in catalyst systems or as catalysts.

Suitable monomers are generally all those which have a polymerizablecarbon-carbon (C═C) double bond. Examples are linear alkenes having from2 to 20 carbon atoms, where the double bond may be in an internal orterminal position, and cyclic or bicyclic alkenes having from 3 to 20carbon atoms, where the C═C double bond can be in an endo or exoposition. The linear and cyclic alkenes can be substituted by functionalgroups such as halogen, an ester group, a —COOH group or a nitrilegroup. Examples of such monomers are vinyl chloride, ethyl acrylate,methyl acrylate, methyl methacrylate and acrylonitrile. The linear andcyclic alkenes are preferably hydrocarbons without heteroatoms. Examplesof such monomers are C₂-C₂₀-alk-1-enes such as ethylene, propylene,1-butene, 1-hexene, 1-octene, 1-decene, cycloalkenes such ascyclopentene, cyclohexene, bicycloalkenes, such as norbornene and alsodienes such as 1,3-butadiene, cyclopentadiene, norbornadiene. Preferrednonaromatic monomers are ethylene, propylene and 1,3-butadiene.

For the purposes of the present invention, preferred aromatic monomersare vinylaromatic compounds of the formula (II)

where the substituents have the following meanings:

R¹³ is hydrogen or C₁-C₄-alkyl,

R¹⁴ to R¹⁸ are, independently of one another, hydrogen, C₁-C₁₂-alkyl,C₆-C₁₈-aryl, halogen or two adjacent radicals together form a cyclicgroup having from 4 to 15 carbon atoms.

Preference is given to using vinylaromatic compounds of the formula IIin which

R¹³ is hydrogen

and

R¹⁴ to R¹ are hydrogen, C₁-C₄-alkyl, chlorine or phenyl or two adjacentradicals together form a cyclic group having from 4 to 12 carbon atoms,resulting in compounds of the formula II which are, for example,naphthalene derivatives or anthracene derivatives.

Examples of such preferred compounds II are:

styrene, p-methylstyrene, p-chlorostyrene, 2,4-dimethylstyrene,1,4-divinylbenzene, 4-vinylbiphenyl, 2-vinylnaphthalene and9-vinylanthracene.

It is also possible to use mixtures of various vinylaromatic compoundsII, but preference is given to using only one vinylaromatic compound.

Particularly preferred vinylaromatic compounds are styrene andp-methylstyrene.

The preparation of vinylaromatic compounds of the formula II is knownper se and is described, for example, in Beilstein 5, 367, 474, 485.

Other monomers which can be used are branched monomers having at leasttwo vinylaromatic functional radicals, for exampletetrakis(4-vinylbenzyl)titanium or tetrakis(4-vinylbenzyl)silane.Further monomers of this type are described in the earlier German PatentApplication 196 34 375.5-44.

In general, the monomers can also be used as a mixture. In this case,the mixing ratio is generally not critical.

The component A) of the catalyst system of the present invention is ametallocene complex of the formula (I)

where the substituents and indices have the following meanings:

R¹ to R¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals R¹ to R⁸ may together form acyclic group having from 4 to 15 carbon atoms, or Si(R¹²)₃,

where R¹² is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

M is a metal of transition groups III to VI of the Periodic Table of theElements or a metal of the lanthanide series,

X are identical or different and are hydrogen, halogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, C₁-C₁₀-alkoxy or C₆-C₁₅-aryloxy

and

n is 1, 2, 3, 4 or 5, where n corresponds to the valence of M minus 1.

Particularly preferred metallocene complexes of the formula I are thosein which

M is a metal of transition group IV of the Periodic Table of theElements, in particular titanium,

X is C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy or halogen and

n is 3.

Mixtures of various metallocene complexes can also be used.

Examples of metallocene complexes (I) according to the present inventionare cyclopenta[I]phenanthrenetitanium trichloride,2-methylcyclopenta[I]phenanthrenetitanium trichloride and2-phenylcyclopenta[I]phenanthrenetitanium trichloride.

The synthesis of the metallocene complexes (I) of the present inventiongenerally starts from 9,10-phenanthrenequinone or ring-substitutedderivatives of this basic molecule. The 9,10-phenanthrenequinone or itsderivative is then generally converted, as described in B Elliasson, J.Org. Chem. (1989), pages 171 to 175 and A. C. Cope, J. Am. Chem. Soc.(1956), pages 2547 to 2551, into the ketone precursor, viz.2,3-dihydro-2-oxo-1H-cyclopenta[I]phenanthrene or its derivative, andfinally by reduction of the keto group with organometallic compounds orhydrogen reductants into the hydrocarbon (III) or its tautomers.

The metallocene complexes (I) of the present invention are generallyobtained by deprotonating the hydrocarbon (III) using a strong,preferably organometallic, base, for example n-butyllithium,subsequently reacting it with a silylation reagent, preferablytrimethylchlorosilane, and finally reacting the product with thetransition metal halide, preferably a halide of transition group IV ofthe Periodic Table of the Elements, for example titanium tetrachloride,zirconium tetrachloride or hafnium tetrachloride.

The further conditions for these reactions are known to those skilled inthe art and are described, for example, in J. Organomet. Chem. (1989),pages 359-370. Preference is given to carrying out the reactions inorganic solvents such as diethyl ether, tetrahydrofuran, toluene ormethylene chloride at a reaction temperature in the range from −78° C.to 150° C.

All the abovementioned reaction steps can be carried out withoutisolation and purification of the intermediates, but the intermediatesare preferably isolated and purified.

As compounds B) capable of forming metallocenium ions, the catalystsystems can comprise open-chain or cyclic aluminoxane compounds.

where R¹⁹ is a C₁-C₄-alkyl group, preferably a methyl or ethyl group,and k is an integer from 5 to 30, preferably from 10 to 25.

The preparation of these oligomeric aluminoxane compounds is usuallycarried out by reacting a solution of trialkylaluminum with water and isdescribed, inter alia, in EP-A 284 708 and U.S. Pat. No. 4,794,096.

The oligomeric aluminoxane compounds obtained in this way are generallyin the form of mixtures of both linear and cyclic chain molecules ofvarious lengths, so that k should be regarded as a mean value. Thealuminoxane compounds can also be present in admixture with other metalalkyls, preferably with aluminum alkyls.

It has been found to be advantageous to use the metallocene complexesand the oligomeric aluminoxane compound in such amounts that the atomicratio of aluminum from the oligomeric aluminoxane compound to thetransition metal from the metallocene complexes is in the range from10:1 to 106:1, preferably in the range from 10:1 to 104:1 and inparticular from 20:1 to 9000:1.

Other compounds B) capable of forming metallocenium ions which can beused are coordination complexes selected from the group consisting ofstrong, uncharged Lewis acids, ionic compounds having Lewis acid cationsand ionic compounds having Bronsted acids as cations.

As strong uncharged Lewis acids, preference is given to compounds of theformula VI

M¹X¹X²X³  (VI)

where

M¹ is an element of main group III of the Periodic Table, in particularB, Al or Ga, preferably B,

X¹,X² and X³ are hydrogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, alkylaryl,arylalkyl, haloalkyl or haloaryl each having from 1 to 10 carbon atomsin the alkyl radical and from 6 to 20 carbon atoms in the aryl radicalor fluorine, chlorine, bromine or iodine, in particular haloaryls,preferably pentafluorophenyl.

Particular preference is given to compounds of the formula VI in whichX¹, X² and X³ are identical, preferably tris(pentafluorophenyl)borane.These compounds and processes for their preparation are known per se andare described, for example, in WO 93/3067.

Suitable ionic compounds having Lewis acid cations are compounds of theformula VII

[(Y^(a+))Q₁Q₂ . . . Q_(z)]^(d+)  (VII)

where

Y is an element of main groups I to VI or of transition groups I to VIIIof the Periodic Table,

Q₁ to Q_(z) are singly negatively charged radicals such as C₁-C₂₈-alkyl,C₆-C₁₅-aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl each having from6 to 20 carbon atoms in the aryl radical and from 1 to 28 carbon atomsin the alkyl radical, C₁-C₁₀-cycloalkyl which may bear C₁-C₁₀-alkylgroups as substituents, halogen, C₁-C₂₈-alkoxy, C₆-C₁₅-aryloxy, silyl ormercaptyl groups,

a is an integer from 1 to 6,

z is an integer from 0 to 5 and

d corresponds to the difference a - z, but d is greater than or equal to1.

Particularly suitable cations are carbonium cations, oxonium cations andsulfonium cations and also cationic transition metal complexes.Particular mention may be made of the triphenylmethyl cation, the silvercation and the 1,1′-dimethylferrocenyl cation.

They preferably have noncoordinating counterions, in particular boroncompounds as are also mentioned in WO 91/09882, preferablytetrakis(pentafluorophenyl)borate.

Ionic compounds having Bronsted acids as cations and preferably likewisenoncoordinating counterions are mentioned in WO 93/3067; the preferredcation is N,N-dimethylanilinium.

It has been found to be particularly useful for the molar ratio of boronfrom the compound capable of forming metallocenium ions to transitionmetal from the metallocene complex to be in the range from 0.1:1 to10:1, in particular in the range from 1:1 to 5:1.

The catalyst systems of the present invention can further comprise anorganometallic compound of main group I, II or III of the Periodic Tableas component C). Examples which may be mentioned are n-butyllithium,butyloctylmagnesium, triethylboron and preferably aluminum compounds.

The aluminum compounds can have, for example, the formula VIII

AlR²⁰R²¹R²²  (VIII),

where

R²⁰ to R²² are hydrogen, fluorine, chlorine, bromine, iodine orC₁-C₁₂-alkyl, preferably C₁—C₈-alkyl.

The radicals R²⁰ and R²¹ are preferably identical and are C₁-C₆-alkylsuch as methyl, ethyl, isobutyl or n-hexyl; R²² is preferably hydrogen.An example which may be mentioned is diisobutylaluminum hydride.

In general, the molar ratio C):I) is in the range from 1:1 to 2000:1,preferably from 10:1 to 800:1.

In general, the molar ratio C):B) and here particularly C):aluminum IV,V is in the range from 0.001:1 to 10,000:1, preferably from 0.01:1 to5000:1.

The catalyst systems of the present invention or at least one of theircomponents A) to C), for example the metallocene complexes(I), can beused in unsupported or supported form.

Suitable support materials are, for example, silica gels, preferablythose of the formula SiO₂.bAl₂O₃, where b is from 0 to 2, preferablyfrom 0 to 0.5; ie. essentially aluminosilicates or silicon dioxide. Thesupports preferably have a particle diameter in the range from 1 to 200μm, in particular from 30 to is 80 μm. Such products are commerciallyavailable, eg. as Silica Gel 332 from Grace.

Further supports are, inter alia, finely divided polyolefins, forexample finely divided polypropylene or polyethylene, but alsopolyethylene glycol, polybutylene terephthalate, polyethyleneterephthalate, polyvinyl alcohol, polystyrene, syndiotactic polystyrene,polybutadiene, polycarbonates or their copolymers.

The polymerization process of the present invention can be carried outessentially at from −78° C. to 150° C., preferably from 0 to 120OC; thepolymerization temperature can also change over time and/or in space. Ithas been found to be advantageous to carry out the polymerization atfrom 60 to 150° C., preferably from 70 to 150° C. It was unexpected thatat such high polymerization temperatures the activity of the catalystsystem of the present invention, calculated as g of polymer/mol oftransition metal×mol of monomer×h, and the molecular weight Mw of thepolymer determined by means of GPC as defined below remains at a highlevel and that, in addition, the syndiotacticity of the polymer,measured by means of extraction with n-butanone, as already described,is still more than 40%, preferably more than 80%.

In general, the process of the present invention is carried out at apressure of from 0.5 to 300 bar, preferably from 1 to 200 bar, inparticular from 1 to 20 bar.

The process of the present invention can be carried out continuously orbatchwise. Various process variants have been found to be useful.

In the polymerization in solution or in bulk monomer, the procedure ispreferably to initially charge the monomer, preferably the above-definedvinylaromatic compound(II), in particular styrene, preferably to heat itto from 60 to 100° C. and then to add the compound B) capable of formingmetallocenium ions, preferably methylaluminoxane ortris(pentafluorophenyl)borane or N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate or a mixture of these components B)and, if desired, also the component C). The component A), if desired ina solvent, is then added. However, it is also possible to mix themetallocene complex A) beforehand with the compound B) capable offorming metallocenium ions and to introduce this mixture into thereactor. In general, polymerization is then carried out over a period offrom 10 to 90 minutes and the polymerization is stopped by addition ofmethanol, the polymer is washed with methanol and dried at from 40 to100° C.

The process of the present invention can also be carried out as adispersion polymerization, as described in DE-A 195 42 356.

Examples of suitable dispersants are styrene-diene two-block copolymersor styrene-diene-styrene three-block copolymers. Preferred dispersionmedia are aliphatic hydrocarbons.

The dispersant is preferably used in an amount of from 1 to 10% byweight, based on the amount of vinylaromatic compounds used. It isadvantageously added to the dispersion to be polymerized as a solutionin the vinylaromatic monomer.

Suitable two-block copolymers can consist of a polymer block made up ofstyrene and a polymer block made up of butadiene, preferably1,4-polybutadiene. The sum of the % by weight of the blocks made up ofstyrene and of butadiene is 100%, with the composition being able tovary. The styrene block can make up from 10 to 90% by weight, preferablyfrom 20 to 80% by weight; the butadiene block can correspondingly makeup from 90 to 10% by weight, preferably from 80 to 20% by weight. Alsosuitable are styrene-butadiene two-block copolymers which may behydrogenated.

Examples of suitable styrene-diene-styrene three-block copolymers arethose in which the diene block comprises polybutadiene or polyisopreneand where the diene block may be hydrogenated or unhydrogenated.

Two-block and three-block copolymers and processes for their preparationare known per se and are described, for example, in ThermoplasticElastomers (1987), N. R. Liegge et al (ed.). Suitable copolymers arealso commercially available, for example Kraton® grades (Shell).

Aliphatic hydrocarbons which are particularly suitable as dispersionmedium are those having from 4 to 10 carbon atoms, for example butane,isobutane, pentane, hexane and heptane or hydrocarbon mixtures.

The preferred procedure in the process of the present invention is todissolve the dispersant in the vinylaromatic compound, add thedispersion medium, preferably in an amount of from 1 to 10% by weightbased on the vinylaromatic compound, then pass the olefinic compoundthrough and add the metallocene catalyst system.

The polymerization can be stopped by addition of protic compounds suchas methanol and the dispersion medium can be removed by increasing thetemperature or, if desired, can be circulated.

Furthermore, the process of the present invention can be carried out asa suspension polymerization as described in DE-A 195 09 785. In thismethod, the monomer or mixture of monomers, preferably the vinylaromaticcompound (II), is generally polymerized at a pressure of from 5 to 300bar, preferably from 6 to 100 bar, in particular from 7 to 50 bar, inthe presence of aliphatic C₁-C₄-hydrocarbons. Preference is given tolinear or branched aliphatic C₃-C₄-hydrocarbons such as propane orisobutane and the catalyst system of the present invention or at leastone of its components A), B) or C) is generally present in supportedform, preferably on porous silica gel.

The process of the present invention can be carried out in variousreactors. Suitable reactors are stirred vessels, kneaders and preferablyextruders.

A particular embodiment of the process comprises carrying it out using acorotating, closely intermeshing and thus self-cleaning twin-screwextruder, preferably in one stage.

The reaction temperature is generally from −78 to 150° C., preferablyfrom 0° to 150° C., in particular from 60 to 150° C. However, it is alsopossible for a temperature gradient of from 0 to 150° C. to be appliedby means of heatable jackets around the reaction tube.

The extruder can have a plurality of individual zones which can beheated to different temperatures.

The external diameter of the corotating, preferably double flightedkneading and conveying elements of the twin-screw extruder is preferablyin the range from 25 to 70 mm, in particular from 30 to 58 mm.

The free gaps between extruder barrel and screw element are in the rangefrom 0.2 to 0.8 mm, in particular from 0.3 to 0.5 mm.

The rotational speed of the screws can be in the range from 3 to 500revolutions per minute, preferably from 5 to 30 revolutions per minute.

The mean residence time in the extruder can be from 0.1 to 240 minutes,preferably from 2 to 20 minutes.

The mean residence time in the extruder can be regulated via the numberof barrel sections. The number of barrel sections is preferably in therange from 6 to 20, in particular from 8 to 12.

Particular preference is given to using 10 barrel sections, whereback-degassing takes place in the first barrel section, the startingmaterials are metered into the second barrel section, the barrelsections 3 to 8 are reaction sections, the barrel sections 9 and 10 canbe heated at a different temperature and the barrel section 10 serves asdischarge barrel.

The process is preferably carried out by mixing the vinylaromaticcompound and, if desired, further monomers defined above, the compoundB) capable of forming metallocenium ions and, if desired, the compoundC) under an inert gas atmosphere and feeding them to the first barrelsection of the extruder. In parallel thereto, a solution or suspensionof the transition metal complex A) can likewise be fed to the firstbarrel section (zone).

As solvents or suspension media, mention may be made of cyclic andacyclic hydrocarbons such as butanes, pentanes, hexanes or heptanes,also aromatic hydrocarbons such as benzene, toluene or ethylbenzene andoxygen-containing hydrocarbons such as tetrahydrofuran,halogen-containing hydrocarbons such as dichloromethane ornitrogen-containing hydrocarbons such as N-methylpiperidine and alsomixtures thereof.

The amount metered in is preferably selected such that from 500 to 2000g/h of the mixture of vinylaromatic compound, if desired furtherabove-defined monomers, components B) and, if used, C) are fed in andfrom 100 to 200 cm³/h of the solution or suspension of the metal complexare fed in.

The polymerization is preferably carried out in the vinylaromaticcompound and, if desired, further above-defined monomers as reactionmedium, ie. in bulk.

The process is technically simple to carry out, high conversions areachieved and the risk of the outlet orifices of the extruder beingblocked by polymer is low.

A further preferred embodiment comprises activating the reaction lmixture comprising vinylaromatic monomers II, if desired furtherabove-defined monomers and the catalyst system comprising A), B) and, ifdesired, C) by premixing and subsequently polymerizing it in a mixingkneader.

The premixing is preferably carried out at a temperature at which thereaction mixture is still liquid and the polymerization does notcommence. Depending on the components used for the reaction mixture,this temperature is in a range from −30 to +140° C., preferably from 0to 70° C. and particularly preferably from to 30° C. Furthermore, in theactivation according to the present invention, the premixing ispreferably carried out with the residence time and the temperature beingselected such that not only commencement of the polymerization reactionbut also damage to the catalyst system are avoided despite sufficientmixing for the activation.

The activation by premixing the reaction mixture is advantageouslycarried out shortly or immediately before the polymerization reaction.The time between activation by premixing and polymerization is from 0 to60 minutes, preferably from 0.01 to 45 minutes and particularlypreferably from 0.1 to 30 minutes.

The premixing is preferably carried out essentially without commencementof a reaction.

The process is advantageously carried out without solvent. In aparticularly preferred embodiment of the process, the monomers usedinitially act as solvent. In addition, it is advantageous to carry outthe process in an inert gas atmosphere, for example of nitrogen orargon, if possible with exclusion of moisture. Hydrogen can also bemetered into the inert gas stream.

The premixing is preferably carried out in such a way that no reactionoccurs. Furthermore, it is advantageous for the polymers to be obtainedin such a form that they can be further processed, for example extruded,essentially immediately after the polymerization. This is preferably thecase when the polymerization in the process is driven to high yields andthe polymer accordingly has a low residual monomer content. Thisresidual monomer content is less than 10% by weight, preferably lessthan 5% by weight and particularly preferably less than 3% by weight,based on the weight of the polymer. The monomers still remaining in thepolymer can be removed, for example, by distillation or by applicationof a vacuum. The process of the present invention is preferably carriedout in a mixing-kneading reactor with an extruder connected downstream,without further work-up steps-, for example distilling off relativelylarge amounts of residual monomer which are obtained, in particular, inthe case of low conversions, having to be carried out. The processtherefore allows further processing of the polymer essentiallyimmediately after its preparation.

If the polymerization of the present invention is carried out in thepresence of branched monomers having at least two vinylaromaticfunctional radicals, for example tetrakis(4-vinylbenzyl)titanium ortetrakis(4-vinylbenzyl)silane, star polymers as described in the earlierGerman Patent Application 196 34 375.5-44 are generally obtained.

The linear polymers obtainable using the process of the presentinvention usually have a molecular weight Mw, determined by gelpermeation chromatography at 135° C. in 1,2,4-trichlorobenzene assolvent against a polystyrene standard, in the range from 20,000 to2×10⁶, preferably in the range from 50,000 to 10⁶.

The syndiotacticity of the polymers obtainable using the process of thepresent invention is generally in the range from 30 to 100%, preferablyin the range from 60 to 100%, in particular from 80 to 100% and veryparticularly preferably in the range from 90 to 100%. Thesyndiotacticity is determined by extracting a baked-out and weighedamount of polymer with 2-butanone for 24 hours, and drying and weighingthe insoluble part of the polymer.

The melting point of the polymers of the present invention, determinedby differential scanning calorimetry (DSC) in accordance with ISO 3146,is in the range from 250 to 285° C., preferably in the range from 260 to280° C.

The polymerization process of the present invention can be carried outat high temperatures, and nevertheless gives polymers having a highmolecular weight MW and a high degree of syndiotacticity.

EXAMPLES

2,3-Dihydro-2-oxo-1H-cyclopenta[I]phenanthrene was prepared as describedby B. Elliasson, J. Org. Chem. (1989), pages 171 to 175 and A. C. Cope,J. Am. Chem. Soc. (1956), pages 2547 to 2551.

Preparation of 3-hydro-2-hydroxy-2-methyl-1H- cyclopenta[I]phenanthrene

8.83 ml of a 3 M solution of methylmagnesium bromide in diethyl ether(26.49 mmol) were added dropwise under protective gas to a suspension of5.00 g of 2,3-dihydro-2-oxo-1H-cyclopenta[I]phenanthrene (21.19 mmol) in20 ml of diethyl ether. After refluxing for 3 hours, the product washydrolyzed by careful addition of 10 ml of 2 N hydrochloric acid.Extracting the mixture three times with diethyl ether, shaking theorganic phase with saturated NaHSO₃ solution, saturated NaHCO₃ solutionand a little water, drying over Na₂SO₄ and evaporating the solution gavea colorless solid.

Yield: 4.68 g (89%)

MS:

M⁺: 248 m/e (33%)

M⁺-CH₃CO: 205 m/e (100%)

NMR (CDCl₃, 600 MHz):

Position ¹H chemical shift Multiplicity Intensity ¹³C chemical shift 4,58.68-8.70 m 2 126.71 125.83 1-3, 6-8 7.77-7.79 m 2 124.76 123.227.59-7.63 m 4 quat. C: 129.83 130.27 123.09 135.02 OH(C—OH) 1.98 bs 179.49 CH₂ 3.44 2d (J=15.8Hz) 4 48.06 Me 1.66 s 3 28.46

Preparation of 1H-2-methylcyclopenta[I]phenanthrene

4.56 g of 3-hydro-2-hydroxy-2-methyl-1H-cyclopenta[I]phenanthrene (18.39mmol) were dewatered by heating for one hour with 0.25 g ofp-toluenesulfonic acid monohydrate in 300 ml of toluene on a waterseparator. The greenish blue solution changed to a reddish color afterdilution with diethyl ether. The resulting solution was shaken withsaturated sodium bicarbonate solution, dried over magnesium sulfate andevaporated. This gave a beige substance which could be purified by rapidfiltration through a glass frit filled with flash silica gel (petroleumether:ethyl acetate).

Yield: 4.02 g (95%)

MS:

M⁺: 230 m/e (100%)

M⁺-Me: 215 m/e (38%)

Elemental analysis:

C₁₈H₁₄

C: (calc.) 93.87 (found) 93.63

H: (calc.) 6.13 (found) 6.17

NMR (250 MHz, CDCl₃)

Multi- Position ¹H chemical shift plicity Intensity ¹³C chemical shift4,5 8.68-8.75 m 2 126.65 126.27 1-3, 6-8 8.10-8.13 m 1 125.51 125.147.93-7.95 m 1 124.60 124.39 7.53-7.65 m 4 123.61 123.43 9 7.07 bs 1123.25 quat. C: 127.50 128.30 129.64 130.19 137.05 140.22 11 3.74 s 242.95 Me 2.33 bs 3 16.94

Preparation of 1H-2-phenylcyclopenta[I]phenanthrene

1 g of 2,3-dihydro-2-oxo-1H-cyclopenta[I]phenanthrene (4.31 mmol) in 100ml of toluene was added dropwise at 0° C. to 2 ml of a 3 M solution ofphenylmagnesium bromide in diethyl ether (6 mmol). The mixture wasallowed to come to room temperature and was stirred for 2 hours. Afterhydrolysis with saturated ammonium chloride solution, the mixture wasextracted with diethyl ether, the organic phase was washed withsaturated sodium chloride solution, dried over magnesium sulfate andevaporated to dryness. The residue was taken up in 100 ml of toluene andrefluxed for 2 hours with 100 mg of p-toluenesulfonic acid. Afteraddition of saturated sodium hydrogen carbonate solution, the mixturewas extracted with diethyl ether, the organic phase was dried overmagnesium sulfate and evaporated. After flash chromatography (petroleumether:ethyl acetate=50:1)

1H-2-phenylcyclopenta[I]phenanthrene was obtained as colorless needles.

Yield: 0.45 g (36%)

MS:

M*⁺: 292 m/e (100%)

M⁺-Ph: 215 m/e (6%)

Elemental analysis:

C₂₃H₁₆

C: (calc.) 94.48 (found) 94.66

H: (calc.) 5.52 (found) 5.63

NMR (CDCl₃, 600 MHz):

¹H Inten- ¹³C Position chemical shift Multiplicity sity chemical shift 18.02 d (J = 7.7 Hz) 1 123.84 2 + 3 7.62-7.56 m 2 126.85, 125.25 4 8.68 d(J = 8.2 Hz) 1 123.51 5 8.72 d (J = 7.1 Hz) 1 123.34 6 + 7 7.66-7.64 m 2125.87, 126.50 8 8.20 d (J = 7.0 Hz) 1 124.29 9 7.79 s 1 124.43 11  4.20s 2  39.22 o-Ph 7.75 d (J = 7.3 Hz) 2 125.50 m-Ph  7.42 t (J = 7.3 Hz) 2128.79 p-Ph 7.29 t (J = 7.3 Hz) 1 127.39 quaternary C 146.43, 139.97137.74, 136.03 130.33, 129.48 128.93, 127.56

General Method of Preparing 1-trimethylsilylcyclopenta[I]-phenanthrenes

The respective cyclopenta[I]phenanthrene (10 mmol) was initially chargedin 20 ml of THF and admixed while cooling in ice with 10 mmol of n-BuLias a 1.6 M solution in hexane. The mixture was allowed to come to roomtemperature and was stirred overnight. The dark green solution wasevaporated to dryness.

1-Trimethylsilylcyclopenta[I]phenanthrene

Yield: 2.05 g (90%), yellow oil

MS:

M⁺: 288 m/e (30%)

M⁺-TMS: 215 m/e (10%)

TMS: 73 m/e (100%)

¹H NMR (CDCl₃, 250 MHz):

Position ¹H chemical shift Multiplicity Intensity Phenanthrene 8.75-8.70m 2 skeleton 8.26-8.22 m 1 8.01-7.97 m 1 +Cp-H  7.65-7.53 m 5 Cp-H6.89-6.86 m 1 Cp-H 4.35 bs 1 TMS −0.05 s 9

1-Trimethylsilyl-2-methylcyclopenta[I]phenanthrene

Yield: 2.60 g (86%), yellow oil

MS:

M⁺: 302 m/e (40%)

M⁺-TMS: 228 m/e (10%)

TMS: 73 m/e (100%)

¹H NMR (CDCl₃, 250 MHz):

Position ¹H chemical shift Multiplicity Intensity Phenanthrene 8.71-8.64m 2 skeleton 8.15-8.12 m 1 7.88-7.85 m 1 7.63-7.48 m 4 Cp-H 7.13 s 1Cp-H 4.15 s 1 Me 2.35 s 3 TMS −0.08 s 9

1-Trimethylsilyl-2-phenylcyclopenta[I]phenanthrene

Yield: 2.76 g (76%), beige solid

MS:

M⁺: 364 m/e (20%)

M⁺-TmS: 291 m/e (7%)

TMS: 73 m/e (65%)

¹H NMR (CDCl₃, 250 MHz):

Position ¹H chemical shift Multiplicity Intensity Phenanthrene 8.73-8.68m 2 skeleton 8.27-8.24 m 1 8.04-8.00 m 1 +Ph-H  7.68-7.53 m 6 Cp-H 7.70s 1 Ph-H 7.45-7.39 m 2 Ph-H 7.32-7.25 m 1 Cp-H 4.91 s 1 TMS −0.30 s 9

General Method of Preparing cyclopenta[I]phenanthrenetitaniumtrichloride and Derivatives

1-Trimethylsilylcyclopenta[I]phenanthrene or its 2-methyl or 2-phenylderivative (batch size corresponding to the amounts obtained above) wasdissolved in 30 ml of methylene chloride and admixed at 0° C. with anequimolar amount of titanium tetrachloride. The orange solutionimmediately became reddish brown. After stirring for 4 hours at roomtemperature, the mixture was cooled to −30° C. overnight. Afterdecanting off the solution, the product could be obtained as a dark redsolid. The yield could be considerably improved by concentrating themother liquor and cooling again.

The numbering of the following cyclopenta[I]phenanthrenes in the NMRtables is according to the general scheme:

Cyclopenta[I]phenanthrenetitanium trichloride

Yield: 1.76 g (53%), red solid

MS:

M⁺: 370 m/e (7%)

M⁺-Cl: 333 m/e (1%)

Lig-H: 215 m/e (100%)

Elemental analysis:

C₁₇H₁₁TiCl₃

C: (calc.) 55.26 (found) 54.77

H: (calc.) 3.00 (found) 3.22

NMR (CDCl₃, 600 MHz): ¹H, ¹³C

¹H Inten- ¹³C Position chemical shift Multiplicity sity chemical shift4,5 8.56 d (J = 8.0 Hz) 2 124.07 2,3,6,7 7.73-7.67 m 4 128.32, 130.071,8 8.23 d (J = 7.4 Hz) 2 125.47  9,11 7.62 d (J = 3.3 Hz) 2 115.42 107.25 t (J = 3.3 Hz) 1 123.09 quaternary C 131.17, 131.10, 127.57, ˜126

2-Methylcyclopenta[I]phenanthrenetitanium trichloride

Yield: 1.75 g (53%), red solid

MS:

M⁺: 384 m/e (8%)

M⁺-Cl: 347 m/e (2%)

M⁺-2Cl: 311 m/e (2%)

MeLig-H: 229 m/e (100%)

Elemental analysis:

C₁₈H₁₃TiCl₃

C: (calc.) 56.37 (found) 55.98

H: (calc.) 3.42 (found) 3.54

NMR (CDCl₃, 600 MHz): ¹H, ¹³C

¹H Inten- ¹³C Position chemical shift Multiplicity sity chemical shift4,5 8.54 d (J = 7.9 Hz) 2 124.02 2,3,6,7 7.71-7.65 m 4 128.25, 129.801,8 8.18 d (J = 7.6 Hz) 2 125.13  9,11 7.47 s 2 115.85 Me 2.73 s 3 18.87 quaternary C 131.64, 130.89, 128.07, 125.19

2-Phenylcyclopenta[I]phenanthrenetitanium chloride

Yield: 2.23 g (66%), red solid

MS:

M⁺: 446 m/e (6%)

PhLig-H: 291 m/e (100%)

Elemental analysis:

C₂₃H₁₅TiCl₃

C: (calc.) 61.99 (found) 61.67

H: (calc.) 3.39 (found) 3.80

NMR (CDCl₃, 600 MHz): ¹H, ¹³C

¹H Inten- ¹³C Position chemical shift Multiplicity sity chemical shift4,5 8.57 d (J = 7.7 Hz) 2 124.46 2,3,6,7 7.7-7.69 m 4 128.66, 130.36 1,88.29 d (J = 7.4 Hz) 2 125.33  9,11 8.03 s 2 110.96 o-Ph 7.99 d (J = 7.4Hz) 2 127.03 m-Ph  7.54 t (J = 7.4 Hz) 2 129.47 p-Ph 7.46 t (J = 7.4 Hz)1 130.80

Styrene Polymerizations

In a 300 ml Schlenk vessel, 50 ml of toluene, 5 ml of styrene hich hadbeen freshly distilled over calcium hydride and 6 ml of ethylaluminoxane(MAO: 1.69 M in toluene) were heated to the desired polymerizationtemperature and stirred for 10 minutes. The titanium catalyst (2.5 μmol,1 ml of a 2.5 mM solution in toluene) was added by means of a syringeand the reaction solution was stirred for from 10 to 20 minutes(Al:Ti=4000:1). The mixture was hydrolyzed by addition of 10% of HCR inmethanol, the precipitated polystyrene was filtered off, washed withfurther methanol and dried overnight at 100° C. Atactic material wasremoved by Soxhlett extraction with 2-butanone for 24 hours. The polymerwas then again dried overnight at 100° C. and weighed to determine thesyndiotactic content. The polymerization results are shown in thefollowing table.

TABLE Polymerization of styrene using variousmetallocene/methylalumninoxane catalysts 50° C.⁶⁾ 75° C. 100° C.Metallocene¹⁾ A²⁾ SY³⁾ M_(w) ⁴⁾ T_(m) ⁵⁾ A SY M_(w) T_(m) A SY M_(w)T_(m) 2-Methylcyclopenta[I]phenanthrenetitanium 10 83 12.3 270.2 26 897.4 267.5 24 82 2.9 259.6 trichloride R = CH₃2-Phenylcyclopenta[I]phenanthrenetitanium 40 85 27.7 267.8 75 92 13.0265.2 45 90 5.8 264.9 trichloride R = C₆H₅ ¹⁾

²⁾A = Activity [× 10⁷ g of polystyrene/(mol of Ti × mol of styrene × h)]³⁾Syndiotacticity [% by weight of material insoluble in 2-butanone]⁴⁾Molecular weight (weight average) [× 10⁴] determined by GPC ⁵⁾Meltingpoint [° C.] determined by DSC ⁶⁾Polymerization temperature

We claim:
 1. A process for preparing polymers based on monomers having aC═C double bond by homopolymerization or copolymerization of thesemonomers in the presence of a catalyst system comprising a metallocenecomplex A) and a compound B) capable of forming metallocenium ions and,optionally, an organometallic compound of main group I, II or III of thePeriodic Table of the Elements C), wherein the metallocene complex A)used is a compound of the formula (I)

where the substituents and indices have the following meanings: R¹ toR¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl which may inturn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl or arylalkyl,where two adjacent radicals R¹ to R⁸ may together form a cyclic grouphaving from 4 to 15 carbon atoms, or Si(R¹²)₃, where R¹² isC₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl, M is a metal oftransition groups III to VI of the Periodic Table of the Elements or ametal of the lanthanide series, X are identical or different and arehydrogen, halogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, C₁-C₁₀-alkoxy orC₆-C₁₅-aryloxy and n is 1, 2, 3, 4 or 5, where n corresponds to thevalence of M minus
 1. 2. A process for preparing polymers as claimed inclaim 1, wherein the polymers are partially crystalline, havesyndiotactic structural units and the monomers used are vinylaromaticcompounds of the formula (II)

where the substituents have the following meanings: R¹³ is hydrogen orC₁-C₄-alkyl, R¹⁴ to R¹⁸ are, independently of one another, hydrogen,C₁-C₁₂-alkyl, C₆-C₁₈-aryl, halogen or two adjacent radicals togetherform a cyclic group having from 4 to 15 carbon atoms, and, optionally,additionally C₂-C₂₀-alkenes or C₃-C₂₀-cycloalkenes.
 3. A catalyst systemwhich is suitable for polymerizing monomers having a C═C double bond andcomprises as active constituents A) a metallocene complex of the formula(I)

 where the substituents and indices have the following meanings: R¹ toR¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl which may inturn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl or arylalkyl,where two adjacent radicals RI to R⁸ may together form a cyclic grouphaving from 4 to 15 carbon atoms, or Si(R¹²)₃, where R¹² isC₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl, M is a metal oftransition groups III to VI of the Periodic Table of the Elements or ametal of the lanthanide series, X are identical or different and arehydrogen, halogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, C₁-C₁₀-alkoxy orC₆-C₁₅-aryloxy and n is 1, 2, 3, 4 or 5, where n corresponds to thevalence of M minus 1, B) a compound capable of forming metalloceniumions and, optionally, C) an organometallic compound of main group I, IIor II of the Periodic Table of the Elements.
 4. A catalyst system asclaimed in claim 3, wherein M is a metal of transition group IV of thePeriodic Table of the Elements.
 5. A metallocene complex of the formula(I)

where the substituents and indices have the following meanings: R¹ toR¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl which may inturn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl or arylalkyl,where two adjacent radicals R¹ to R⁸ may together form a cyclic grouphaving from 4 to 15 carbon atoms, or Si(R¹²) 3, where R¹² isC₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl, M is a metal oftransition groups III to VI of the Periodic Table of the Elements or ametal of the lanthanide series, X are identical or different and arehydrogen, halogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, C₁-C₁₀-alkoxy orC₆-C₁₅-aryloxy and n is 1, 2, 3, 4 or 5, where n corresponds to thevalence of M minus
 1. 6. Cyclopenta[I]phenanthrenetitanium trichloride,2-methylcyclopenta[I]phenanthrenetitanium trichloride and2-phenylcyclopenta[I]phenanthrenetitanium trichloride.
 7. A polymerbased on monomers having a C═C double bond, obtainable byhomopolymerization or copolymerization of these monomers in the presenceof a catalyst system comprising as active constituents a metallocenecomplex A) and a compound B) capable of forming metallocenium ions and,optionally, an organometallic compound of main group I, II or III of thePeriodic Table of the Elements C), wherein the metallocene complex A)used is a compound of the formula (I)

where the substituents and indices have the following meanings: R¹ toR¹¹ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl which may inturn bear C₁-C₆-alkyl groups as substituents, C₆-C₁₅-aryl or arylalkyl,where two adjacent radicals R¹ to R⁸ may together form a cyclic grouphaving from 4 to 15 carbon atoms, or Si(R¹²)₃, where R¹² isC₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl, M is a metal oftransition groups III to VI of the Periodic Table of the Elements or ametal of the lanthanide series, X are identical or different and arehydrogen, halogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, C₁-C₁₀-alkoxy orC₆-C₁₅-aryloxy and n is 1, 2, 3, 4 or 5, wherein n corresponds to thevalence of M minus
 1. 8. A fiber, film or molding comprising a polymeras claimed in claim 7.